A Safe and Strong Support for Photovoltaic Systems on Pitched Roofs. Pitched Roof Structures for Framed and Frameless Photovoltaic Modules. The S:FLEX pitched roof system allows for easy installation of framed and frameless photovoltaic modules on old and new buildings. The S:FLEX pitched roof mounting structure has numerous preassembled parts. Variable system height capability enables a level photovoltaic array on uneven roof surfaces.